6 Bugs and ideas

If you find a bug or misfeature, don’t hesitate to report it, by
using M-x report-emacs-bug. The same applies to feature requests.
It is best to discuss one thing at a time. If you find several
unrelated bugs, please report them separately.

Below is a list of some known problems with Eshell version 2.4.2,
which is the version included with Emacs 22.

Documentation incomplete

Differentiate between aliases and functions

Allow for a Bash-compatible syntax, such as:

alias arg=blah
function arg () { blah $* }

‘for i in 1 2 3 { grep -q a b && *echo has it } | wc -l’ outputs result after prompt

In fact, piping to a process from a looping construct doesn’t work in
general. If I change the call to eshell-copy-handles in
eshell-rewrite-for-command to use eshell-protect, it seems
to work, but the output occurs after the prompt is displayed. The whole
structured command thing is too complicated at present.

Error with bc in eshell-test

On some XEmacs system, the subprocess interaction test fails
inexplicably, although bc works fine at the command prompt.

Eshell does not delete *Help* buffers in XEmacs 21.1.8+

In XEmacs 21.1.8, the *Help* buffer has been renamed such that
multiple instances of the *Help* buffer can exist.

Pcomplete sometimes gets stuck

You press TAB, but no completions appear, even though the
directory has matching files. This behavior is rare.

‘grep python $<rpm -qa>’ doesn’t work, but using ‘*grep’ does

This happens because the grep Lisp function returns immediately,
and then the asynchronous grep process expects to examine the
temporary file, which has since been deleted.

Problem with C-r repeating text

If the text before point reads "./run", and you type C-r r u
n, it will repeat the line for every character typed.

Backspace doesn’t scroll back after continuing (in smart mode)

Hitting space during a process invocation, such as make, will
cause it to track the bottom of the output; but backspace no longer
scrolls back.

It’s not possible to fully unload-feature Eshell

Menu support was removed, but never put back

Using C-p and C-n with rebind gets into a locked state

This happened a few times in Emacs 21, but has been irreproducible
since.

If an interactive process is currently running, M-! doesn’t work

Use a timer instead of sleep-for when killing child processes

Piping to a Lisp function is not supported

Make it so that the Lisp command on the right of the pipe is repeatedly
called with the input strings as arguments. This will require changing
eshell-do-pipeline to handle non-process targets.

Input redirection is not supported

See the above entry.

Problem running less without arguments on Windows

The result in the Eshell buffer is:

Spawning child process: invalid argument

Also a new less buffer was created with nothing in it…
(presumably this holds the output of less).

If less.exe is invoked from the Eshell command line, the
expected output is written to the buffer.

Note that this happens on NT-Emacs 20.6.1 on Windows 2000. The term.el
package and the supplied shell both use the cmdproxy program
for running shells.

Implement ‘-r’, ‘-n’ and ‘-s’ switches for cp

Make M-5 M-x eshell switch to “*eshell<5>*”, creating if need be

‘mv dirfile.tar’ does not remove directories

This is because the tar option –remove-files doesn’t do so. Should it
be Eshell’s job?

Bind standard-output and standard-error

This would be so that if a Lisp function calls print, everything
will happen as it should (albeit slowly).

When an extension module fails to load, ‘cd /’ gives a Lisp error

If a globbing pattern returns one match, should it be a list?

Make sure syntax table is correct in Eshell mode

So that M-DEL acts in a predictable manner, etc.

Allow all Eshell buffers to share the same history and list-dir

There is a problem with script commands that output to /dev/null

If a script file, somewhere in the middle, uses ‘> /dev/null’,
output from all subsequent commands is swallowed.

Split up parsing of text after ‘$’ in esh-var.el

Make it similar to the way that esh-arg.el is structured.
Then add parsing of ‘$[?\n]’.

With zsh, the glob above expands to all files named
Root in directories named CVS.

Typing ‘echo ${locate locate}/bin<TAB>’ results in a Lisp error

Perhaps it should interpolate all permutations, and make that the
globbing result, since otherwise hitting return here will result in
“(list of filenames)/bin”, which is never valuable. Thus, one could
cat only C backup files by using ‘ls ${identity *.c}~’.
In that case, having an alias command name glob for
identity would be useful.

Once symbolic mode is supported for umask, implement chmod in Lisp

Create eshell-expand-file-name

This would use a data table to transform things such as ‘~+’,
‘...’, etc.

Abstract em-smart.el into smart-scroll.el

It only really needs: to be hooked onto the output filter and the
pre-command hook, and to have the input-end and input-start markers.
And to know whether the last output group was “successful.”

It means that files beginning with a dot should be included in the
glob match.

A comma in a predicate list should mean OR

At the moment, this is not supported.

Error if a glob doesn’t expand due to a predicate

An error should be generated only if eshell-error-if-no-glob is
non-nil.

‘(+ RET SPC TAB’ does not cause indent-according-to-mode to occur

Create eshell-auto-accumulate-list

This is a list of commands for which, if the user presses RET, the
text is staged as the next Eshell command, rather than being sent to the
current interactive process.

Display file and line number if an error occurs in a script

wait doesn’t work with process ids at the moment

Enable the direct-to-process input code in em-term.el

Problem with repeating ‘echo ${find /tmp}’

With smart display active, if RET is held down, after a while it
can’t keep up anymore and starts outputting blank lines. It only
happens if an asynchronous process is involved…

I think the problem is that eshell-send-input is resetting the
input target location, so that if the asynchronous process is not done
by the time the next RET is received, the input processor thinks
that the input is meant for the process; which, when smart display is
enabled, will be the text of the last command line! That is a bug in
itself.

In holding down RET while an asynchronous process is running,
there will be a point in between termination of the process, and the
running of eshell-post-command-hook, which would cause
eshell-send-input to call eshell-copy-old-input, and then
process that text as a command to be run after the process. Perhaps
there should be a way of killing pending input between the death of the
process, and the post-command-hook.

Allow for a more aggressive smart display mode

Perhaps toggled by a command, that makes each output block a smart
display block.

Create more meta variables

‘$!’

The reason for the failure of the last disk command, or the text of the
last Lisp error.

‘$=’

A special associate array, which can take references of the form
‘$=[REGEXP]’. It indexes into the directory ring.

Eshell scripts can’t execute in the background

Support zsh’s “Parameter Expansion” syntax, i.e., ‘${name:-val}’

Write an info alias that can take arguments

So that the user can enter ‘info chmod’, for example.

Create a mode eshell-browse

It would treat the Eshell buffer as a outline. Collapsing the outline
hides all of the output text. Collapsing again would show only the
first command run in each directory

Allow other revisions of a file to be referenced using ‘file{rev}’

This would be expanded by eshell-expand-file-name (see above).

Print “You have new mail” when the “Mail” icon is turned on

Implement M-| for Eshell

Implement input redirection

If it’s a Lisp function, input redirection implies xargs (in a
way…). If input redirection is added, also update the
file-name-quote-list, and the delimiter list.

Allow ‘#<wordarg>’ as a generic syntax

With the handling of word specified by an
eshell-special-alist.

In eshell-eval-using-options, allow a :complete tag

It would be used to provide completion rules for that command. Then the
macro will automagically define the completion function.

For eshell-command-on-region, apply redirections to the result

So that ‘+ > 'blah’ would cause the result of the + (using
input from the current region) to be inserting into the symbol
blah.

If an external command is being invoked, the input is sent as standard
input, as if a ‘cat <region> |’ had been invoked.

If a Lisp command, or an alias, is invoked, then if the line has no
newline characters, it is divided by whitespace and passed as arguments
to the Lisp function. Otherwise, it is divided at the newline
characters. Thus, invoking + on a series of numbers will add
them; min would display the smallest figure, etc.

Write eshell-script-mode as a minor mode

It would provide syntax, abbrev, highlighting and indenting support like
emacs-lisp-mode and shell-mode.

In the history mechanism, finish the Bash-style support

This means ‘!n’, ‘!#’, ‘!:%’, and ‘!:1-’ as separate
from ‘!:1*’.

Support the -n command line option for history

Implement fc in Lisp

Specifying a frame as a redirection target should imply the currently active window’s buffer

Implement ‘>func-or-func-list’

This would allow for an “output translators”, that take a function to
modify output with, and a target. Devise a syntax that works well with
pipes, and can accommodate multiple functions (i.e., ‘>'(upcase
regexp-quote)’ or ‘>'upcase’).

Allow Eshell to read/write to/from standard input and output

This would be optional, rather than always using the Eshell buffer.
This would allow it to be run from the command line (perhaps).

Write a help command

It would call subcommands with --help, or -h or
/?, as appropriate.

Implement stty in Lisp

Support rc’s matching operator, e.g., ‘~ (list) regexp’

Implement bg and fg as editors of eshell-process-list

Using bg on a process that is already in the background does
nothing. Specifying redirection targets replaces (or adds) to the list
current being used.

Have jobs print only the processes for the current shell

How can Eshell learn if a background process has requested input?

Support ‘2>&1’ and ‘>&’ and ‘2>’ and ‘|&’

The syntax table for parsing these should be customizable, such that the
user could change it to use rc syntax: ‘>[2=1]’.

Allow ‘$_[-1]’, which would indicate the last element of the array

Make ‘$x[*]’ equal to listing out the full contents of ‘x’

Return them as a list, so that ‘$_[*]’ is all the arguments of the
last command.

Copy ANSI code handling from term.el into em-term.el

Make it possible for the user to send char-by-char to the underlying
process. Ultimately, I should be able to move away from using term.el
altogether, since everything but the ANSI code handling is already part
of Eshell. Then, things would work correctly on MS-Windows as well
(which doesn’t have /bin/sh, although term.el tries to use
it).

Make the shell spawning commands be visual

That is, make (su, bash, telnet,
rlogin, rsh, etc.) be part of
eshell-visual-commands. The only exception is if the shell is
being used to invoke a single command. Then, the behavior should be
based on what that command is.

Create a smart viewing command named open

This would search for some way to open its argument (similar to opening
a file in the Windows Explorer).

Alias read to be the same as open, only read-only

Write a tail command which uses view-file

It would move point to the end of the buffer, and then turns on
auto-revert mode in that buffer at frequent intervals—and a
head alias which assumes an upper limit of
eshell-maximum-line-length characters per line.

Make dgrep load dired, mark everything, then invoke dired-do-search

Write mesh.c

This would run Emacs with the appropriate arguments to invoke Eshell
only. That way, it could be listed as a login shell.

Use an intangible PS2 string for multi-line input prompts

Auto-detect when a command is visual, by checking TERMCAP usage

The first keypress after M-x watson triggers ‘eshell-send-input’

Make / electric

So that it automatically expands and corrects pathnames. Or make
pathname completion for Pcomplete auto-expand ‘/u/i/std<TAB>’ to
‘/usr/include/std<TAB>’.

Write the pushd stack to disk along with last-dir-ring

Add options to eshell/cat which would allow it to sort and uniq

Implement wc in Lisp

Add support for counting sentences, paragraphs, pages, etc.

Once piping is added, implement sort and uniq in Lisp

Implement touch in Lisp

Implement comm in Lisp

Implement an epatch command in Lisp

This would call ediff-patch-file, or ediff-patch-buffer,
depending on its argument.

Have an option such that ‘ls -l’ generates a dired buffer

Write a version of xargs based on command rewriting

That is, ‘find X | xargs Y’ would be indicated using ‘Y
${find X}’. Maybe eshell-do-pipelines could be changed to
perform this on-thy-fly rewriting.

Write an alias for less that brings up a view-mode buffer

Such that the user can press SPC and DEL, and then q
to return to Eshell. It would be equivalent to:
‘X > #<buffer Y>; view-buffer #<buffer Y>’.